Early Ford V-8 Club Forum

EFV-8 Club Forum / General Ford Discussion / Charging Question

Reply to Discussion | New Discussion << previous || next >>

Posted By Discussion Topic: Charging Question -- page: 1 2 3     MGG 08-10-2017 @ 1:47 PM reply profile send p.m. Member Posts: 85 Joined: Jul 2014 Scenario: 1940 V-8, 6-Volts, positive ground, 2-Brush later generator with ground terminal wired to the base of the voltage regulator, good battery, new voltage regulator, new ignition wiring, new charge system wiring. Test of the generator and it shot up to 30 amps. Voltage across the battery terminals before start = 6.45 with digital meter. Voltage after running 10 minutes and engine shut off = 6.70 Voltage after 20 minutes on the Battery Tender (indicating full charge), engine shut off = 6.64 Voltage 30 minutes later with engine shut off = 6.51 My meter was too jumpy to get anything across the terminals while the engine was running. Question: The original dash volt meter never got fully into the green area while running, only to the very edge of it, yet the battery after starting and running the engine for only 10 minutes appears to be at, or nearly at, full charge. Is this within the accuracy range of the gauge or do I still have a charging problem? I did not run any lights or other accessories. Thanks - Mark G. This message was edited by MGG on 8-10-17 @ 1:48 PM cliftford 08-10-2017 @ 2:22 PM reply profile send p.m. Senior Posts: 845 Joined: Jan 2014 First, an analog meter is much better, doing this type of work. 2nd, I would tend to believe a good quality analog meter over the original guage. sarahcecelia 08-10-2017 @ 3:23 PM reply profile send p.m. Senior Posts: 1183 Joined: Mar 2013 30 amps is good for that generator (it's a 30 amp unit); that's what my 1940 6 volt puts out. Did you polarize the system after all of that work? You should have. I had the EXACT same problem your having, and replaced the volt gauge. Now It goes into the green a little at idle and at about 1200 rev's it goes about 1/3 into the green.I found a NOS gauge on Ebay! If you find that that is the problem, to install the gauge isn't too bad, but you have to pull the radio to get to it. Check the volts between the "Batt" terminal on the regulator and a GOOD ground to see if it's getting to the regulator from the generator. Maybe the wire from the generator to that terminal on the regulator is bad? Remove some paint on the generator brackett. to ensure it has a good ground. I hope this is a help to you. Regards, Steve Lee TomO 08-14-2017 @ 9:12 AM reply profile send p.m. Senior Posts: 7250 Joined: Oct 2009 The marks on the gauge are : L = 2 volts, line left of the N is 6 volts, the N range is 6.75 volt at the left end to 8.25 volts at the right end, the line marked H is 9 volts. Your voltage regulator should regulate the generator output to 7.2 - 7.6 Volts. This would put it at the left 1/4 of the green area. The gauge should read battery voltage at idle and take some time(about 1 min) at 30mph or higher to move into the green area. You only need to worry when the gauge reads below the unmarked line (voltage is too low due to the generator or voltage regulator limiting the voltage or a bad battery) or above the right 1/4 of the green area, or above 8 volts (voltage regulator not controlling the output of the generator). Tom MGG 08-15-2017 @ 9:44 AM reply profile send p.m. Member Posts: 85 Joined: Jul 2014 Thanks guys. Yes, I did polarize the system and I have an analog meter on order. All wiring is new and all connections are tight and bright. The metal is bare where the generator mounts. I will do some more testing when the meter arrives. TomO 08-16-2017 @ 6:53 AM reply profile send p.m. Senior Posts: 7250 Joined: Oct 2009 The main purpose of the BATT gauge is to let you know that there is an unusual condition, like a bad battery, bad generator or voltage regulator. It is not designed to give you an accurate voltage reading. My description was for the 39 Gauge. The 40 gauge operation is the same, just the markings are different. The 1940 Gauge right end of the first red zone is 6.2 volts, the right end of the yellow zone is 7.1 Volts and the right end of the green zone is 8.25 volts. These readings could be off by 0.2V - 0.4V At 6.35 Volts the gauge should read in the yellow zone. Your gauge should only read in the green zone when you are driving at more than 35mph without any accessories turned on. The regulator should allow the generator to put out 7.2-7.6 volts at engine speeds above 1,200 rpm. This is measured at the BAT terminal of the voltage regulator with all accessories turned off. If your needle gets to the center of the yellow area at 6.8 volts, it is within the tolerance of the gauge. Drive your car for 20 or 30 minutes with no lights, radio or heater and at speeds above 35 mph. If your electrical system is working correctly, your gauge should just enter the green band while driving at speed. It can take as long as 1 minute after idling at a stop light to enter the green area. If your voltage regulator is only allowing 6.8 volts, you may have a problem with charging the battery when you have to drive for more than an hour with the lights on. Tom MGG 08-16-2017 @ 8:03 AM reply profile send p.m. Member Posts: 85 Joined: Jul 2014 In testing for the voltage at the battery terminal of the V/R do you unhook the other terminals? I assume the negative lead of my meter goes on the terminal and the positive lead touches to a ground spot such as the head? Do you need to re-polarize after the test? Thanks TomO 08-17-2017 @ 7:04 AM reply profile send p.m. Senior Posts: 7250 Joined: Oct 2009 You do NOT need to disconnect any wires to make the voltage check. If you do disconnect any of the wires at the voltage regulator, you will not get an usable reading. Connect the black lead of your voltmeter to the Bat terminal of the voltage regulator, the red lead goes to ground, Strt the engine and increase the rpm to around 1,500 and read the meter. You do not have to polarize the generator after making this test. You only have to polarize the generator when it is not charging or charging in the wrong polarity. This can happen when the generator is replaced with one that has spent a long time on the shelf, when the voltage regulator is replaced and when the battery is connected backwards. Tom MGG 08-17-2017 @ 5:48 PM reply profile send p.m. Member Posts: 85 Joined: Jul 2014 You are very clear. Thanks so much!! MGG 08-18-2017 @ 2:06 PM reply profile send p.m. Member Posts: 85 Joined: Jul 2014 In the V/R test, do the connections have to be made before starting the engine or does it matter? This message was edited by MGG on 8-20-17 @ 6:30 AM

<< previous || next >>

PAGE: 1 2 3

NOTE: YOU MUST BE A REGISTERED USER AND BE LOGGED IN TO POST (and reply to) messages in this forum. If you are a first time user, please click the CREATE A NEW ACCOUNT in the masthead above to register and Log In. After that, all you do is LOG IN to enjoy using this site.

DISCLAIMER: The V-8 Club does no independent testing of any of the opinions, thoughts or suggestions presented in the website on the Forum, in the Tech Tips section, or any section. A reader should consider the website to be a forum wherein differing solutions to a particular set of circumstances may be discussed. Ultimately, the selection of an item for an individual's vehicle must be based upon the independent study of the vehicle owner in consultation with people in the hobby and restoration experts.

EFV-8 Club Forum Home | Back to Home Page | Contact the Webmaster

Copyright © 2009 - EFV-8.org
Powered by < CF FORUM > v.2.1